#include <stdio.h>
void main()
{
    int a,i,b,n;
    printf(" There are following friendly -numbers pair smaller than 3000:\n");
    for(a=1;a<3000;a++){
        for(b=0;i<=a/2;i++)
          if(! (a%i))b+=i;
        for(n=0,i=1;i<=b/2;i++)
          if(! (b%i))n+=i;
        if(n==a && a<b)
          printf(" %4d..%4d",a,b);
    }
}